Carboxyl group-containing polymer composition

Abstract

The present invention provides a carboxyl group-containing polymer composition that exhibits excellent anti-soil redeposition ability in fabric washing. The carboxyl group-containing polymer composition contains a carboxyl group-containing polymer, which includes specific ratios of a structure unit (a) derived from an acrylic acid-based monomer (A) and a structure unit (b) derived from a sulfonic acid group-containing monomer (B) and has a specific weight average molecular weight, and a specific amount of an adduct of a hydrogen sulfite to the acrylic acid-based monomer (A).

The invention claimed is: 
     
       1. A carboxyl group-containing polymer composition comprising a carboxyl group-containing polymer,
 wherein the carboxyl group-containing polymer consists of a structure unit (a) derived from an acrylic acid-based monomer (A) at a level of from 62 to 70% by mass and a structure unit (b) derived from a sulfonic acid group-containing monomer (B) at a level of from 30 to 38% by mass based on 100% by mass of all structure units derived from all monomers in the carboxyl group-containing polymer,
 the carboxyl group-containing polymer has a weight average molecular weight of 23,000 to 50,000, and 
 wherein the carboxyl group-containing polymer composition further comprises an adduct of a hydrogen sulfite to the acrylic acid-based monomer (A), and 
 the adduct is present at a level of 0.3 to 5% by mass based on 100% by mass of a solids content of the carboxyl group-containing polymer composition. 
 
 
     
     
       2. The carboxyl group-containing polymer composition according to  claim 1 , wherein the structure unit (a) is at a level of from 64 to 70% by mass and a structure unit (b) is at a level of from 30 to 36% by mass based on 100% by mass of all structure units derived from all monomers in the carboxyl group-containing polymer. 
     
     
       3. The carboxyl group-containing polymer composition according to  claim 1 , wherein the structure unit (a) is at a level of from 66 to 70% by mass and a structure unit (b) is at a level of from 30 to 34% by mass based on 100% by mass of all structure units derived from all monomers in the carboxyl group-containing polymer. 
     
     
       4. The carboxyl group-containing polymer composition according to  claim 1 , wherein the carboxyl group-containing polymer has a weight average molecular weight of 23,000 to 45,000. 
     
     
       5. The carboxyl group-containing polymer composition according to  claim 1 , wherein the carboxyl group-containing polymer has a weight average molecular weight of 24,000 to 40,000. 
     
     
       6. The carboxyl group-containing polymer composition according to  claim 1 , wherein the carboxyl group-containing polymer has a weight average molecular weight of 25,000 to 38,000. 
     
     
       7. The carboxyl group-containing polymer composition according to  claim 1 , wherein the carboxyl group-containing polymer has a weight average molecular weight of 27,000 to 33,000.